Two Indian judges on Monday confirmed the death sentence for the sole surviving gunman of the 2008 Mumbai attacks, in which 10 Islamist gunmen laid siege to the city, killing 166 people.

The Bombay High Court dismissed the claim by Pakistani national Mohammed Ajmal Amir Kasab that he was wrongfully convicted of taking part in the attacks, likened in India to those in the United States on September 11, 2001.

The judges also threw out the state's appeal against a lower court's decision to acquit two Indian nationals who were accused of providing hand-drawn maps to the 10 gunmen.

Kasab, who has not attended the appeal for security reasons but has been able to follow proceedings via video link, looked at the floor as the judgment was handed down, news channel NDTV said.

"Harsh penalty of death is required in some cases, especially this one, and the court would be sending a wrong signal to society if any penalty less than death is given," judges Ranjana Desai and R.V. More said in their ruling.

"Kasab has never shown any remorse after his arrest and we have observed that even on video conference he has not shown any signs of regret," they added.

The 23-year-old was found guilty last May of a string of offences including waging war against India, murder, attempted murder and terrorist acts after a trial at a maximum security prison court in Mumbai.

During the trial, the prosecution produced weighty fingerprint, DNA, eye-witness, CCTV and other evidence against him.

In the appeal, which began last October, Kasab's legal team asked for a retrial, arguing that his trial lawyer was not given sufficient time to wade through the 11,000-page charge sheet before the case began.

They also claimed that prosecution evidence and witnesses were manipulated.

Under Indian law, death sentence cases have to be referred to the local state high court. The judges can uphold the sentence, reduce it, order a retrial or overturn the conviction.

Kasab has a further right of appeal to the Supreme Court in New Delhi and as a last resort to India's president for clemency.

One of his lawyers, Farhana Shah, told reporters outside court: "We will inform Kasab of his legal rights. Kasab has to decide. If he wishes (to appeal) he can do so."

Prosecutor Ujjwal Nikam flashed a victory sign on the court steps and described the judgment as a "historic verdict".

"Truth has prevailed," he said. "We appealed to the court that this was the rarest of rare cases and that he should be hanged, which the court approved."

Kasab was found to have been one of the two gunmen responsible for the bloodiest episode in the three-day attacks, when 52 people were killed at Mumbai's main railway station on November 26, 2008.

A number of senior Mumbai police officers, including the head of the Maharashtra state anti-terrorism squad, were killed as the gunmen fled the scene of carnage.

Three luxury hotels, a popular tourist restaurant and a Jewish centre were also attacked.

India blames the banned, Pakistan-based Islamist group Lashkar-e-Taiba for masterminding the attacks, which led to the suspension of fragile peace talks between the two neighbours and rivals.

New Delhi and Islamabad only this month agreed to resume dialogue.

The chief minister of Maharashtra state, of which Mumbai is the capital, welcomed the judgment and called on Pakistan to prosecute those behind the planning, financing and equipping of the attacks.

"I appeal to the union government (in New Delhi) to bring all international pressure on Pakistan to unearth and bring to book the guilty," Prithviraj Chavan told reporters.

In the case of Kasab's co-accused, the high court judges agreed with the trial judge that there was "no corroboration of evidence to prove involvement of Faheem Ansari and Sabauddin Ahmed".

The men's defence teams had said a Pakistani-American man, David Coleman Headley, conducted the reconnaissance. He was arrested in 2009 and has admitted to scouting out targets.